Chemical processing operations, including petroleum refining and petrochemical operations, are energy intensive. It is often necessary to conduct these operations at high temperatures using high temperature heat sources including but not limited to steam. After the steam and other hot streams have performed the intended functions, there remains unutilized energy. Refineries and petrochemical facilities typically utilize only 70% of the input energy needed to conduct processing of crude oil to products.
In an effort to increase energy efficiency, it is desirable to recover and utilize unutilized heat. One prior art method disclosed in U.S. Pat. No. 5,823,003 to Rosser et al attempts to make use of waste heat and apply such heat to an adsorbent material in order to release an adsorbed gas at higher pressure, which in turn can be used in a refrigeration cycle that contains an expansion valve. U.S. Pat. No. 5,823,003 discloses the use of a zeolite-water pairing.
Current methods to obtain refrigeration from sorbent materials in chemical process applications have limitations. Often the sorbent materials and gases employed in sorption systems require other process equipment such as pumping devices, that are expensive to maintain, unreliable and require a large allocation of space. Such limitations often render the recovery of the unutilized heat economically unsustainable.
Accordingly, there remains a need to make unutilized heat recovery efforts more cost-effective by providing the opportunity to utilize lower and higher grades of unutilized heat, to reduce equipment and space requirements of the process. There also remains a need to provide other uses, besides refrigeration, of the fluid released from unutilized heat-charged sorbent materials.